A commercial aircraft may include thousands of threaded fasteners that clamp up different components. The threaded fasteners may be installed at specified torques.
However, a specified torque might not produce a specified preload (e.g., due to friction between the fastener and nut). To ensure that the specified preload is achieved, the fasteners are oversized and overtorqued.
Oversized fasteners are undesirable. For a commercial aircraft having thousands of fasteners, the use of oversized fasteners increases the weight of the aircraft and, therefore, increases fuel costs and other operating costs.